Mobile station apparatus

ABSTRACT

A mobile station (MS) obtains a parameter, performs transmission of a preamble, and sets a counter incremented based on transmission of the preamble. The MS is able to indicate a random access problem corresponding to one transmission timing cell group in a case where the counter reaches the parameter+1 and the transmission of the preamble is performed on the one transmission timing cell group, where the one transmission timing cell group being one of the plurality of transmission timing cell groups, and the MS is able to not indicate a random access problem corresponding to another transmission timing cell group in a case where the counter reaches the parameter+1 and the transmission of the preamble is performed on the another transmission timing cell group, where the another transmission timing cell group being one of the plurality of transmission timing cell groups.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation application of co-pending U.S.application Ser. No. 15/341,734 filed Nov. 2, 2016, which is aContinuation of U.S. application Ser. No. 14/754,004 filed Jun. 29, 2015(Issued as U.S. Pat. No. 9,538,556 on Jan. 3, 2017), which is aContinuation of U.S. application Ser. No. 13/814,424 filed on Mar. 4,2013 (Issued as U.S. Pat. No. 9,094,989 on Jul. 28, 2015), which is aNational Phase of PCT International Application No. PCT/JP2011/066740filed on Jul. 22, 2011, which claims priority under 35 U.S.C. § 119(a)to Japanese Patent Application No. 2010-177918 filed in Japan on Aug. 6,2010. All of the above applications are hereby expressly incorporated byreference into the present application.

TECHNICAL FIELD

The present invention relates to a base station apparatus, a mobilestation apparatus, a mobile communication system, a communicationmethod, a control program, and an integrated circuit that are used forefficiently executing random access.

BACKGROUND ART

In 3GPP (3rd Generation Partnership Project), the W-CDMA scheme has beenstandardized as a 3rd generation cellular mobile communication scheme,and the services thereof have sequentially been available. Also, HSDPAwith higher communication speed has been standardized, and the servicesthereof have been available.

Also, in 3GPP, standardization of evolved 3rd generation radio access(Evolved Universal Terrestrial Radio Access, hereinafter referred to as“EUTRA”) is progressing. As a downlink communication scheme of EUTRA,the OFDM (Orthogonal Frequency Division Multiplexing) scheme, which isresistant to multipath interference and is suitable for high-speedtransmission, is employed. As an uplink communication scheme, the DFT(Discrete Fourier Transform)-spread OFDM scheme of the SC-FDMA (SingleCarrier-Frequency Division Multiple Access) scheme, in which the PAPR(Peak to Average Power Ratio) of a transmission signal can be decreased,is employed in view of the cost and power consumption of mobile stationapparatuses.

In 3GPP, discussions over Advanced-EUTRA, which is a further developmentof EUTRA, have begun. Advanced-EUTRA is based on the assumption that aband with a bandwidth of up to 100 MHz is used in each of uplink anddownlink, and that communication is performed at transmission rates ofup to 1 Gbps or more in downlink and up to 500 Mbps or more in uplink.

Advanced-EUTRA is directed to realizing a 100 MHz band at a maximum bycombining a plurality of EUTRA bands, each having a bandwidth of 20 MHzor less, so as to be compatible with EUTRA mobile station apparatuses.In Advanced-EUTRA, each EUTRA band of 20 MHz or less is called acomponent carrier (CC) (NPL 3). A combination of one downlink componentcarrier and one uplink component carrier constitutes one cell. Also,only one downlink component carrier may constitute one cell.

CITATION LIST Non Patent Literature

NPL 1: 3GPP TS (Technical Specification) 36.300, V9.30 (2010-03),Evolved Universal Terrestrial Radio Access (E-UTRA) and EvolvedUniversal Terrestrial Radio Access Network (E-UTRAN), Overalldescription Stage 2

NPL 2: 3GPP TS (Technical Specification) 36.321, V9.20 (2010-03),Evolved Universal Terrestrial Radio Access (E-UTRA) Medium AccessControl (MAC) protocol specification

NPL 3: 3GPP TS (Technical Report) 36.814, V9.00 (2010-03), EvolvedUniversal Terrestrial Radio Access (E-UTRA) Further advancements forE-UTRA physical layer aspects

SUMMARY OF INVENTION Technical Problem

In a case where a mobile station apparatus communicates with a basestation apparatus by using a plurality of cells, the mobile stationapparatus may connect to the base station apparatus via a repeater orthe like. In such a case, the reception timing of each downlinkcomponent carrier in the mobile station apparatus may vary amongindividual cells. Furthermore, a transmission timing for the basestation apparatus may vary among individual uplink component carriers ofindividual cells. Thus, it is necessary to adjust transmission timingsin individual uplink component carriers of individual cells.

However, in a case where it is necessary to adjust transmission timingsin individual cells, if uplink synchronization is lost, such as at thetime of initial access or handover, random access processing isnecessary for individual cells. In a case where each mobile stationapparatus is allocated with a plurality of cells and where a pluralityof random access processing operations are simultaneously executed inthe individual cells, the processing executed in the mobile stationapparatus becomes complicated. In addition, since each mobile stationapparatus executes a plurality of random access processing operations,collisions of random access preambles among the mobile stationapparatuses increase.

The present invention has been made in view of these circumstances, andan object of the invention is to provide a base station apparatus, amobile station apparatus, a mobile communication system, a communicationmethod, a control program, and an integrated circuit that enableefficient random access in a case where transmission timings on the sideof mobile station apparatuses vary among individual cells.

Solution to Problem

(1) In order to achieve the above-described object, an embodiment of thepresent invention takes the following measures. That is, a base stationapparatus of an embodiment of the present invention is a base stationapparatus applied to a mobile communication system in which randomaccess from a mobile station apparatus to a base station apparatus isexecuted. The base station apparatus allocates a plurality of cells tothe mobile station apparatus, groups the cells into groups in each ofwhich cells have an identical transmission timing in the mobile stationapparatus, notifies the mobile station apparatus of transmission timingsdetermined for the individual groups, permits the mobile stationapparatus to execute random access using any one of the cells includedin the groups, and notifies the mobile station apparatus of randomaccess execution information about the cell for which random access ispermitted.

(2) The base station apparatus of an embodiment of the present inventionpermits both of contention based random access and non-contention basedrandom access, or only non-contention based random access for the cellfor which random access is permitted.

(3) The base station apparatus of an embodiment of the present inventionpermits both of contention based random access and non-contention basedrandom access for any one of the cells for which random access ispermitted, and permits non-contention based random access for anotherone of the cells for which random access is permitted.

(4) In a case where the cell for which random access is permitted ischanged, the base station apparatus of an embodiment of the presentinvention notifies the mobile station apparatus of random accessexecution information about a cell for which random access is newlypermitted.

(5) A base station apparatus of an embodiment of the present inventionis a base station apparatus applied to a mobile communication system inwhich random access from a mobile station apparatus to a base stationapparatus is executed. The base station apparatus allocates a pluralityof cells to the mobile station apparatus, groups the cells into groupsin each of which cells have an identical transmission timing in themobile station apparatus, and notifies the mobile station apparatus oftransmission timings determined for the individual groups. Also, thebase station apparatus sets, for the mobile station apparatus, any oneof the cells included in any one of the groups as a first cell, any oneof the cells included in another one of the groups as a second cell, andcells other than the first cell and the second cell as third cells, andnotifies the mobile station apparatus of system information and settinginformation about the cells.

(6) In the base station apparatus of an embodiment of the presentinvention, system information about the first cell and the second cellincludes random access execution information, and system informationabout the third cells does not include random access executioninformation.

(7) The base station apparatus of an embodiment of the present inventionpermits contention based random access and non-contention based randomaccess for the first cell, and permits non-contention based randomaccess for the second cell.

(8) A mobile station apparatus of an embodiment of the present inventionis a mobile station apparatus applied to a mobile communication systemin which random access from a mobile station apparatus to a base stationapparatus is executed. The mobile station apparatus receives, from thebase station apparatus, allocation information about a plurality ofcells, information about grouping of the cells into groups in each ofwhich cells have an identical transmission timing, and random accessexecution information about one cell in each of the groups, andtransmits a random access preamble for only a cell to which the randomaccess execution information is set.

(9) In a case where the mobile station apparatus of an embodiment of thepresent invention newly receives random access execution informationfrom the base station apparatus after the cell for which random accessis permitted has been changed by the base station apparatus, the mobilestation apparatus discards random access execution information that hasalready been obtained.

(10) In a case where the number of transmissions of a random accesspreamble for the cell for which both of contention based random accessand non-contention based random access are permitted by the base stationapparatus exceeds a maximum number of retransmissions, the mobilestation apparatus of an embodiment of the present invention determinesthat random access has failed, and, in a case where the number oftransmissions of a random access preamble for the cell for which onlynon-contention based random access is permitted exceeds the maximumnumber of retransmissions, the mobile station apparatus determines thatrandom access has not failed.

(11) In a case where the mobile station apparatus of an embodiment ofthe present invention receives random access instruction informationabout the cell for which only non-contention based random access ispermitted by the base station apparatus and where the random accessinstruction information indicates contention based random access, themobile station apparatus discards the received random access instructioninformation.

(12) In a case where the mobile station apparatus of an embodiment ofthe present invention receives random access instruction informationabout a cell other than the cell for which random access is permitted bythe base station apparatus, the mobile station apparatus discards thereceived random access instruction information.

(13) A mobile station apparatus of an embodiment of the presentinvention is a mobile station apparatus applied to a mobilecommunication system in which random access from a mobile stationapparatus to a base station apparatus is executed. In the base stationapparatus, cells are grouped into groups in each of which cells have anidentical transmission timing, any one of the cells included in any oneof the groups is set as a first cell, any one of the cells included inanother one of the groups is set as a second cell, cells other than thefirst cell and the second cell are set as third cells, and the mobilestation apparatus receives system information and setting informationabout the cells from the base station apparatus, and sets, for theindividual cells, the received system information and settinginformation about the cells.

(14) The mobile station apparatus of an embodiment of the presentinvention transmits a random access preamble only for the first cell andthe second cell.

(15) In a case where the mobile station apparatus of an embodiment ofthe present invention receives change instruction information forchanging the first cell or the second cell from the base stationapparatus, the mobile station apparatus discards random access executioninformation about the first cell before change or the second cell beforechange.

(16) In a case where the number of transmissions of a random accesspreamble for the second cell exceeds a maximum number ofretransmissions, the mobile station apparatus of an embodiment of thepresent invention determines that random access has not failed.

(17) In a case where the mobile station apparatus of an embodiment ofthe present invention receives random access instruction informationabout the second cell from the base station apparatus and where thereceived random access instruction information indicates contentionbased random access, the mobile station apparatus discards the receivedrandom access instruction information.

(18) In a case where the mobile station apparatus of an embodiment ofthe present invention receives random access instruction informationabout the third cells from the base station apparatus, the mobilestation apparatus discards the received random access instructioninformation.

(19) A mobile communication system of an embodiment of the presentinvention includes the base station apparatus according to (1) and themobile station apparatus according to (8), or the base station apparatusaccording to (5) and the mobile station apparatus according to (13).

(20) A communication method of an embodiment of the present invention isa communication method for a base station apparatus applied to a mobilecommunication system in which random access from a mobile stationapparatus to a base station apparatus is executed. The communicationmethod includes allocating a plurality of cells to the mobile stationapparatus, grouping the cells into groups in each of which cells have anidentical transmission timing in the mobile station apparatus, notifyingthe mobile station apparatus of transmission timings determined for theindividual groups, permitting the mobile station apparatus to executerandom access using any one of the cells included in the groups, andnotifying the mobile station apparatus of random access executioninformation about the cell for which random access is permitted.

(21) A communication method of an embodiment of the present invention isa communication method for a base station apparatus applied to a mobilecommunication system in which random access from a mobile stationapparatus to a base station apparatus is executed. The communicationmethod includes allocating a plurality of cells to the mobile stationapparatus, grouping the cells into groups in each of which cells have anidentical transmission timing in the mobile station apparatus, notifyingthe mobile station apparatus of transmission timings determined for theindividual groups, setting, for the mobile station apparatus, any one ofthe cells included in any one of the groups as a first cell, any one ofthe cells included in another one of the groups as a second cell, andcells other than the first cell and the second cell as third cells, andnotifying the mobile station apparatus of system information and settinginformation about the cells.

(22) A control program of an embodiment of the present invention is acontrol program for a base station apparatus applied to a mobilecommunication system in which random access from a mobile stationapparatus to a base station apparatus is executed. The control programincludes commands to cause a computer to be able to read and execute aseries of processes. The series of processes include a process ofallocating a plurality of cells to the mobile station apparatus, aprocess of grouping the cells into groups in each of which cells have anidentical transmission timing in the mobile station apparatus, andnotifying the mobile station apparatus of transmission timingsdetermined for the individual groups, and a process of permitting themobile station apparatus to execute random access using any one of thecells included in the groups, and notifying the mobile station apparatusof random access execution information about the cell for which randomaccess is permitted.

(23) A control program of an embodiment of the present invention is acontrol program for a base station apparatus applied to a mobilecommunication system in which random access from a mobile stationapparatus to a base station apparatus is executed. The control programincludes commands to cause a computer to be able to read and execute aseries of processes. The series of processes include a process ofallocating a plurality of cells to the mobile station apparatus, aprocess of grouping the cells into groups in each of which cells have anidentical transmission timing in the mobile station apparatus, andnotifying the mobile station apparatus of transmission timingsdetermined for the individual groups, a process of setting, for themobile station apparatus, any one of the cells included in any one ofthe groups as a first cell, a process of setting any one of the cellsincluded in another one of the groups as a second cell, a process ofsetting cells other than the first cell and the second cell as thirdcells, and a process of notifying the mobile station apparatus of systeminformation and setting information about the cells.

(24) An integrated circuit of an embodiment of the present invention isan integrated circuit that is mounted in a base station apparatus tocause the base station apparatus to implement a plurality of functions.The integrated circuit causes the base station apparatus to implement aseries of functions. The series of functions includes a function ofallocating a plurality of cells to the mobile station apparatus, afunction of grouping the cells into groups in each of which cells havean identical transmission timing in the mobile station apparatus, andnotifying the mobile station apparatus of transmission timingsdetermined for the individual groups, and a function of permitting themobile station apparatus to execute random access using any one of thecells included in the groups, and notifying the mobile station apparatusof random access execution information about the cell for which randomaccess is permitted.

(25) An integrated circuit of an embodiment of the present invention isan integrated circuit that is mounted in a base station apparatus tocause the base station apparatus to implement a plurality of functions.The integrated circuit causes the base station apparatus to implement aseries of functions. The series of functions includes a function ofallocating a plurality of cells to the mobile station apparatus, afunction of grouping the cells into groups in each of which cells havean identical transmission timing in the mobile station apparatus, andnotifying the mobile station apparatus of transmission timingsdetermined for the individual groups, a function of setting, for themobile station apparatus, any one of the cells included in any one ofthe groups as a first cell, a function of setting any one of the cellsincluded in another one of the groups as a second cell, a function ofsetting cells other than the first cell and the second cell as thirdcells, and a function of notifying the mobile station apparatus ofsystem information and setting information about the cells.

Advantageous Effects of Invention

According to the present invention, unnecessary random access processingdoes not occur even in a case where a plurality of component carriersare allocated to one mobile station apparatus in an Advanced-EUTRAsystem. This enables efficient random access.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a block diagram illustrating the configuration of a mobilestation apparatus according to a first embodiment of the presentinvention.

FIG. 2 is a block diagram illustrating the configuration of a basestation apparatus according to the first embodiment of the presentinvention.

FIG. 3A is a diagram illustrating an example configuration of cellsaccording to the first embodiment of the present invention.

FIG. 3B is a diagram illustrating an example configuration of cellsaccording to the first embodiment of the present invention.

FIG. 4A is a diagram illustrating an example configuration of cellsaccording to a second embodiment of the present invention.

FIG. 4B is a diagram illustrating an example configuration of cellsaccording to the second embodiment of the present invention.

FIG. 5 is a diagram illustrating a channel configuration in EUTRA.

FIG. 6 is a diagram illustrating the configuration of uplink in EUTRA.

FIG. 7 is a sequence chart illustrating a contention based random accessprocedure.

FIG. 8 is a sequence chart illustrating a non-contention based randomaccess procedure.

FIG. 9 is a diagram illustrating an example of a sequence group inEUTRA.

FIG. 10 is an explanatory diagram of downlink component carriers inAdvanced-EUTRA.

FIG. 11 is an explanatory diagram of uplink component carriers inAdvanced-EUTRA.

FIG. 12 is a diagram illustrating an example in which a base stationapparatus and a mobile station apparatus communicate with each other viarepeaters.

DESCRIPTION OF EMBODIMENTS

Hereinafter, embodiments of the present invention will be described withreference to the drawings. The downlink of EUTRA is constituted by adownlink pilot channel DPiCH, a downlink synchronization channel DSCH, aphysical downlink shared channel PDSCH, a physical downlink controlchannel PDCCH, and a physical broadcast channel PBCH.

The uplink of EUTRA is constituted by an uplink pilot channel UPiCH, arandom access channel RACH, a physical uplink shared channel PUSCH, anda physical uplink control channel PUCCH.

FIG. 5 is a diagram illustrating a channel configuration in EUTRA, andFIG. 6 is a diagram illustrating the configuration of uplink in EUTRA.One block is constituted by twelve sub-carriers and seven OFDM symbols.Two blocks constitute one resource block. Regarding the random accesschannel RACH, one random access channel is provided in one sub-frame, sothat accesses from many mobile station apparatuses, for example, mobilestation apparatuses 1-1 to 1-3 (hereinafter the mobile stationapparatuses 1-1 to 1-3 are collectively referred to as mobile stationapparatuses 1), can be dealt with.

The arrangement configuration (frequency positions and time positions)of random access channels RACH is notified from a base station apparatus3 to the mobile station apparatuses 1, as a part of system informationabout the base station apparatus 3. The random access channels RACH arearranged at certain intervals. The random access channels RACH, theregion of the physical uplink shared channel PUSCH, and the region ofthe physical uplink control channel PUCCH are separated as illustratedin FIG. 6. One random access channel RACH is constituted by using sixresource blocks. The random access channel is used for, in uplink,achieving uplink synchronization between the mobile station apparatus 1and the base station apparatus 3 (adjusting a timing of transmissionfrom the mobile station apparatus 1 to the base station apparatus 3).

A random access procedure has two variants, namely contention basedrandom access and non-contention based random access (NPL 1).

FIG. 7 is a diagram illustrating a procedure of contention based randomaccess. Contention based random access is random access in whichcollision is likely to occur among the mobile station apparatuses 1.Contention based random access is performed, for example, at the time ofinitial access in a state where connection to (communication with) thebase station apparatus 3 has not been established, or at the time ofsending a scheduling request when uplink data transmission occurs in themobile station apparatus 1 in a state where connection to the basestation apparatus 3 has been established but uplink synchronization islost.

FIG. 8 is a diagram illustrating a procedure of non-contention basedrandom access. Non-contention based random access is random access inwhich collision does not occur among the mobile station apparatuses 1.In non-contention based random access, the mobile station apparatus 1starts random access in response to an instruction from the base stationapparatus 3 in a special case, for example, at the time of handover orin a case where the transmission timing of the mobile station apparatus1 is not valid, in order to quickly achieve uplink synchronizationbetween the mobile station apparatus 1 and the base station apparatus 3when the connection between the base station apparatus 3 and the mobilestation apparatus 1 has been established but uplink synchronizationtherebetween is lost (NPL 1). Non-contention based random access isinstructed by a message of an RRC layer (Radio Resource Control: Layer3) and control data of the physical downlink control channel PDCCH.

In the case of accessing a random access channel RACH, the mobilestation apparatus 1 transmits only a random access preamble. The randomaccess preamble is constituted by a preamble portion and a CP (Cyclicprefix) portion. In the preamble portion, a CAZAC (Constant AmplitudeZero Auto-Correlation Zone Code) sequence serving as a signal patternrepresenting information is used. Sixty-four types of sequences areprepared and six-bit information is expressed.

As illustrated in FIG. 9, CAZAC sequences used for a random accesspreamble are roughly classified into a sequence used for contentionbased random access (random sequence or random preamble) and a sequenceused for non-contention based random access (dedicated sequence ordedicated preamble). Information about generation of the random accesspreamble is notified as system information from the base stationapparatus 3 to the mobile station apparatus 1. Also, random accessinformation included in the system information notified from the basestation apparatus 3 includes information about the maximum number oftransmissions of a random access preamble and the transmission power forthe random access preamble.

A contention based random access procedure will be briefly describedwith reference to FIG. 7. First, a mobile station apparatus 1 among themobile station apparatuses 1 transmits a random access preamble to thebase station apparatus 3 (message 1 (1), step S1). Then, the basestation apparatus 3 receives the random access preamble and transmits aresponse to the random access preamble (random access response) to themobile station apparatus 1 (message 2 (2), step S2). The mobile stationapparatus 1 transmits a message of an upper layer (Layer 2/Layer 3) onthe basis of scheduling information included in the random accessresponse (message 3 (3), step S3). The base station apparatus 3transmits a collision confirmation message to the mobile stationapparatus 1 which has received the upper layer message of (3) (message 4(4), step S4). Note that contention based random access is also referredto as random preamble transmission.

A non-contention based random access procedure will be briefly describedwith reference to FIG. 8. First, the base station apparatus 3 notifiesthe mobile station apparatus 1 of a preamble number (or a sequencenumber) and a random access channel number to be used (message 0 (1′),step S11). The mobile station apparatus 1 transmits a random accesspreamble of the specified preamble number to the specified random accesschannel RACH (message 1 (2′), step S12). Then, the base stationapparatus 3 receives the random access preamble and transmits a responseto the random access preamble (random access response) to the mobilestation apparatus 1 (message 2 (3′), step S13). If the value of thenotified preamble number is 0, contention based random access isperformed. Note that non-contention based random access is also referredto as dedicated preamble transmission.

Referring to FIG. 7, the contention based random access procedure willbe described in detail. First, the mobile station apparatus 1 selectsone random sequence from a random sequence group on the basis of adownlink radio channel condition (path-loss) and the size of message 3,generates a random access preamble on the basis of the selected randomsequence, and transmits the random access preamble by using a randomaccess channel RACH (message 1 (1)).

The base station apparatus 3 detects the random access preambletransmitted from the mobile station apparatus 1, and then calculates anamount of difference in transmission timing between the mobile stationapparatus 1 and the base station apparatus 3 by using the random accesspreamble, performs scheduling for transmitting an L2/L3 message(specifies the position of an uplink radio resource and a transmissionformat (message size)), allocates Temporary C-RNTI (Cell-Radio NetworkTemporary Identity: mobile station apparatus identificationinformation), arranges RA-RNTI, which represents a response (randomaccess response) addressed to the mobile station apparatus 1 which hastransmitted the random access preamble using the random access channelRACH, to the physical downlink control channel PDCCH, and transmits therandom access response, which includes transmission timing information,scheduling information, Temporary C-RNTI, and the preamble number(sequence number) of the received preamble, to the physical downlinkshared channel PDSCH (message 2 (2)).

The mobile station apparatus 1 detects the RA-RNTI in the physicaldownlink control channel PDCCH, and then determines the content of therandom access response message arranged in the physical downlink sharedchannel PDSCH. If the random access response message includes thepreamble number corresponding to the transmitted random access preamble,the mobile station apparatus 1 adjusts the transmission timing inaccordance with the transmission timing information, and transmits anL2/L3 message which includes information identifying the mobile stationapparatus 1, such as C-RNTI (or Temporary C-RNTI) or IMSI (InternationalMobile Subscriber Identity), by using the scheduled radio resource andtransmission format (message 3 (3)). After adjusting the transmissiontiming, the mobile station apparatus 1 starts a transmission timingtimer in which the adjusted transmission timing is valid. Thetransmission timing becomes invalid when timeout occurs. While thetransmission timing is valid, the mobile station apparatus 1 is capableof transmitting data to the base station apparatus 3. When thetransmission timing is invalid, the mobile station apparatus 1 iscapable of transmitting only a random access preamble.

The mobile station apparatus 1 waits for a random access responsemessage from the base station apparatus 3 for a certain period. If themobile station apparatus 1 does not receive a random access responsemessage which includes the preamble number of the transmitted randomaccess preamble, the mobile station apparatus 1 retransmits the randomaccess preamble.

The base station apparatus 3 receives the L2/L3 message from the mobilestation apparatus 1, and then transmits a collision confirmation(contention resolution) message for determining whether or not collisionis being occurred among the mobile station apparatuses 1-1 to 1-3 to themobile station apparatus 1 by using C-RNTI (or Temporary C-RNTI) or IMSIincluded in the received L2/L3 message (message 4 (4)).

If the mobile station apparatus 1 does not detect a random accessresponse message which includes the preamble number corresponding to thetransmitted random access preamble within a certain period, or fails totransmit the message 3, or does not detect identification informationabout the mobile station apparatus 1 itself in the collisionconfirmation message within a certain period, the mobile stationapparatus 1 retransmits the random access preamble (message 1 (1)) (NPL2). If the number of transmissions of the random access preamble exceedsthe maximum number of transmissions of the random access preambleindicated by the system information, the mobile station apparatus 1determines that random access has failed, and stops the communicationwith the base station apparatus 3. If the random access procedure hasbeen successfully completed, transmission and reception of control datafor establishing connection are performed between the base stationapparatus 3 and the mobile station apparatus 1.

After the random access procedure, the transmission timing is updated inthe following manner: the base station apparatus 3 measures the uplinkpilot channel UPiCH transmitted from the mobile station apparatus 1,calculates timing information, and notifies the mobile station apparatus1 of the calculated transmission timing.

In 3GPP, discussions over Advanced-EUTRA, which is a further developmentof EUTRA, have begun. Advanced-EUTRA is based on the assumption that aband with a bandwidth of up to 100 MHz is used in each of uplink anddownlink, and that communication is performed at transmission rates ofup to 1 Gbps or more in downlink and up to 500 Mbps or more in uplink.

FIG. 10 is an explanatory diagram of downlink component carriers inAdvanced-EUTRA. FIG. 11 is an explanatory diagram of uplink componentcarriers in Advanced-EUTRA.

Advanced-EUTRA is directed to realizing a 100 MHz band at a maximum bycombining a plurality of EUTRA bands, each having a bandwidth of 20 MHzor less, so as to be compatible with EUTRA mobile station apparatuses 1.In Advanced-EUTRA, each EUTRA band of 20 MHz or less is called acomponent carrier (CC) (NPL 3). A combination of one downlink componentcarrier and one uplink component carrier constitutes one cell. Also,only one downlink component carrier may constitute one cell.

The base station apparatus 3 allocates, among a plurality of cells, oneor more cells suitable for the communication capacity and communicationcondition of the mobile station apparatus 1. The mobile stationapparatus 1 transmits and receives data by using the allocated cell orcells. In a case where the mobile station apparatus 1 communicates withthe base station apparatus 3 by using a plurality of cells, the mobilestation apparatus 1 may connect to the base station apparatus 3 via arepeater or the like, as illustrated in FIG. 12. In such a case, thereception timing of each downlink component carrier in the mobilestation apparatus 1 and/or the transmission timing of each uplinkcomponent carrier for the base station apparatus 3 may vary amongindividual cells. Particularly, if the transmission timing of eachuplink component carrier for the base station apparatus 3 varies, it isnecessary for the mobile station apparatus 1 to adjust transmissiontimings in individual uplink component carriers of individual cells.

First Embodiment Description of Configuration

FIG. 1 is a diagram illustrating the configuration of the mobile stationapparatus 1 according to an embodiment of the present invention. Themobile station apparatus 1 includes a radio unit 101, transmissionprocessing units 103-1 to 103-5 (hereinafter, the transmissionprocessing units 103-1 to 103-5 are collectively referred to astransmission processing units 103), reception processing units 105-1 to105-5 (hereinafter, the reception processing units 105-1 to 105-5 arecollectively referred to as reception processing units 105), atransmission data control unit 107, a control data extracting unit 109,a random access preamble generating unit 111, transmission timingadjusting units 113-1 to 113-5 (hereinafter, the transmission timingadjusting units 113-1 to 113-5 are collectively referred to astransmission timing adjusting units 113), a control unit 115, and ascheduling unit 117. The scheduling unit 117 includes a control dataanalyzing unit 119, a UL scheduling unit 121, a control data creatingunit 123, and a cell management unit 125. In this embodiment, in orderto describe an example in which the mobile station apparatus 1-1 iscapable of receiving signals using five cells, five transmissionprocessing units 103, five reception processing units 105, and fivetransmission timing adjusting units 113 are provided.

User data and control data are input to the transmission data controlunit 107. The transmission data control unit 107 allocates individualpieces of data to individual channels of uplink component carriers ofindividual cells, and transmits the pieces of data to the transmissionprocessing units 103-1 to 103-5, in response to an instruction from thecontrol unit 115. The transmission processing units 103-1 to 103-5modulate and encode the pieces of data received from the transmissiondata control unit 107, perform series/parallel conversion on inputsignals, perform DFT-IFFT (Inverse Fast Fourier Transform), and alsoperform OFDM signal processing such as insertion of CP, therebygenerating OFDM signals. The transmission timing adjusting units 113-1to 113-5 adjust transmission timings of signals to be output usingindividual uplink component carriers of individual cells, in accordancewith transmission timing information received from the control unit 115.After the adjustment of transmission timings, the signals areup-converted to a radio frequency by the radio unit 101 and aretransmitted from a transmission antenna. Note that a random accesspreamble is transmitted without the transmission timing thereof beingadjusted, even if a transmission timing is set.

The radio unit 101 down-converts radio signals received from the antennaand supplies the radio signals to the reception processing units 105.The reception processing units 105-1 to 105-5 perform FFT (Fast FourierTransform) processing, decoding, demodulation processing, and so forthon the signals received from the radio unit 101, and supply demodulateddata to the control data extracting unit 109. Also, the receptionprocessing units 105-1 to 105-5 measure radio channel characteristics ofthe downlink component carriers of the individual cells, and supplymeasurement results to the scheduling unit 117.

The control data extracting unit 109 refers to C-RNTI (mobile stationapparatus identification information) which is arranged in the physicaldownlink control channels PDCCH of the individual cells and downlinkscheduling information in the input data, and determines whether or notthe input data is addressed to the own mobile station apparatus. If theinput data is addressed to the own mobile station apparatus, the controldata extracting unit 109 divides the data in the physical downlinkshared channels PDSCH modulated by the reception processing units 105-1to 105-5 into control data and user data. Then, the control dataextracting unit 109 supplies the control data to the scheduling unit117, and supplies the user data to an upper layer. Also, the controldata extracting unit 109 supplies uplink scheduling information includedin the physical downlink control channels PDCCH to the scheduling unit117. Also, in a case where the control data extracting unit 109 detectsRA-RNTI (Random Access-Radio Network Temporary Identity) aftertransmitting a random access preamble, the control data extracting unit109 supplies a random access response message to the scheduling unit117. Also, the control data extracting unit 109 instructs the schedulingunit 117 to respond to the received data. The control unit 115 controlsthe radio unit 101, the transmission processing units 103-1 to 103-5,the reception processing units 105-1 to 105-5, the transmission datacontrol unit 107, and the control data extracting unit 109, in responseto instructions from the scheduling unit 113.

The scheduling unit 117 includes the control data analyzing unit 119,the UL scheduling unit 121, the control data creating unit 123, and thecell management unit 125. The control data creating unit 123 createscontrol data, and creates a response to downlink data received by thecontrol data extracting unit 109. The control data analyzing unit 119analyzes the control data received from the control data extracting unit109. The control data analyzing unit 119 supplies system informationabout the cells, allocation information about the cells, a random accessresponse message, and random access instruction information which arereceived from the base station apparatus 3 to the cell management unit125, and supplies random access information included in the systeminformation to the random access preamble generating unit 111.

The UL scheduling unit 121 controls the transmission data control unit107 on the basis of scheduling information about uplink data. Also, theUL scheduling unit 121 instructs the cell management unit 125 to executerandom access on the basis of control information received from an upperlayer.

The cell management unit 125 manages the cells which are set by the basestation apparatus 3, and manages system information notified from thebase station apparatus 3, such as the configuration of physical channelsof the individual cells, transmission power information, and randomaccess information. In a case where random access to the base stationapparatus 3 is executed, the cell management unit 125 determines a cellwith which a random access preamble is to be transmitted, randomlyselects a sequence to be used on the basis of the downlink radio channelcharacteristic information received from the reception processing units105-1 to 105-5 and the transmission data size of the message 3 by usingrandom access information about the cell to be used for random access,and notifies the random access preamble generating unit 111 ofinformation about the selected cell and a sequence number (preamblenumber). The details of random access will be described below.

Also, the cell management unit 125 determines the content of the randomaccess response received from the control data analyzing unit 119. Whenthe cell management unit 125 detects the preamble number of thetransmitted random access preamble, the cell management unit 125supplies transmission timing information to any of the transmissiontiming adjusting units 113-1 to 113-5 related to the cell used forrandom access, and supplies allocated radio resource information to theUL scheduling unit 121. After determining a contention resolutionmessage, the cell management unit 125 ends the random access procedure.Also, the cell management unit 125 extracts a sequence number (preamblenumber) and a random access channel number from the random accessinstruction information received from the control data analyzing unit119, and supplies the cell information, the sequence number (preamblenumber), and the random access channel number to the random accesspreamble generating unit 111.

The sequence selected by the mobile station apparatus 1 is referred toas a random sequence (random preamble), and the sequence specified bythe base station apparatus 3 is referred to as a dedicated sequence(dedicated preamble). In a case where a cell to be used is not specifiedby the base station apparatus 3, the mobile station apparatus 1 executesrandom access by using the uplink component carrier of the cell withwhich the random access instruction information has been received. Also,in a case where a sequence to be used is not specified, the mobilestation apparatus 1 selects a sequence from among random sequences.

In a case where the random access preamble generating unit 111 isnotified of cell information and a sequence number from the schedulingunit 117, the random access preamble generating unit 111 creates apreamble portion and a CP portion on the basis of the random accessinformation about the specified cell and the sequence number, andthereby generates a random access preamble. Also, the random accesspreamble generating unit 111 selects a random access channel position tobe used on the basis of the random access information about thespecified cell, and allocates the generated random access preamble tothe selected random access channel position. In a case where the randomaccess preamble generating unit 111 is notified of a cell number, asequence number, and a random access channel number from the schedulingunit 117, the random access preamble generating unit 111 creates apreamble portion and a CP portion on the basis of the random accessinformation about the specified component carrier and the sequencenumber, and thereby generates a random access preamble. Also, the randomaccess preamble generating unit 111 selects a random access channelposition to be used on the basis of the random access information aboutthe specified cell and a random access number. Then, the random accesspreamble generating unit 111 allocates the generated random accesspreamble to the selected random access channel position in the specifiedcomponent carrier.

FIG. 2 illustrates a configuration diagram of the base station apparatus3 according to an embodiment of the present invention. The base stationapparatus 3 includes a radio unit 201, transmission processing units203-1 to 203-5 (hereinafter, the transmission processing units 203-1 to203-5 are collectively referred to as transmission processing units203), reception processing units 205-1 to 205-5 (hereinafter, thereception processing units 205-1 to 205-5 are collectively referred toas reception processing units 205), a transmission data control unit207, a control data extracting unit 209, preamble detecting units 211-1to 211-5 (hereinafter, the preamble detecting units 211-1 to 211-5 arecollectively referred to as preamble detecting units 211), a controlunit 213, and a scheduling unit 215 (base-station-side scheduling unit).The scheduling unit 215 includes a DL scheduling unit 217, a ULscheduling unit 219, a control data creating unit 221, and a cellmanagement unit 223. In this embodiment, an example of a case where thebase station apparatus 3 has five cells is described, and thus fivetransmission processing units 203, five reception processing units 205,and five preamble detecting units 211 are provided.

In accordance with an instruction from the control unit 213, thetransmission data control unit 207 maps user data and control data, thatis, maps control data to the physical downlink control channels PDCCH,the downlink synchronization channels DSCH, the downlink pilot channelsDPiCH, the physical broadcast channels PBCH, and the physical downlinkshared channels PDSCH of the downlink component carriers of theindividual cells, and maps the data to be transmitted to the individualmobile station apparatuses 1 to the physical downlink shared channelsPDSCH.

The transmission processing units 203-1 to 203-5 modulate and encode thedata to be transmitted, perform series/parallel conversion on inputsignals, and perform OFDM signal processing such as IFFT transform,insertion of CP, and filtering, thereby generating OFDM signals. Theradio unit 201 up-converts the OFDM-modulated data to a radio frequency,and transmits the data to the mobile station apparatuses 1. Also, theradio unit 201 receives uplink data from the mobile station apparatuses1, down-converts the data to baseband signals, and supplies the receivedsignals to the reception processing units 205-1 to 205-5 or the preambledetecting units 211-1 to 211-5. The reception processing units 205-1 to205-5 perform demodulation processing by using the uplink schedulinginformation received from the control unit 213 in view of thetransmission processing executed by the mobile station apparatuses 1, soas to demodulate data. Also, the reception processing units 205-1 to205-5 measure radio channel characteristics by using the uplink pilotchannels UPiCH, and supply the results to the scheduling unit 215. It isassumed that a single carrier scheme, such as DFT-spread OFDM, is usedas an uplink communication scheme. However, a multi-carrier scheme suchas an OFDM scheme may be used.

The control data extracting unit 209 determines whether or not receiveddata is correct or incorrect, and notifies the scheduling unit 215 of adetermination result. If the received data is correct, the control dataextracting unit 209 divides the received data into user data and controldata. The control unit 213 controls the radio unit 201, the transmissionprocessing units 203-1 to 203-5, the reception processing units 205-1 to205-5, the transmission data control unit 207, and the control dataextracting unit 209, on the basis of instructions from the schedulingunit 215.

The scheduling unit 215 includes the DL scheduling unit 217 whichperforms downlink scheduling, the UL scheduling unit 219 which performsuplink scheduling, the control data creating unit 221, and the cellmanagement unit 223. The DL scheduling unit 217 performs scheduling formapping user data and control data to individual downlink channels, onthe basis of the downlink radio channel information notified from themobile station apparatuses 1, data information about individual usersnotified from an upper layer, and the control data created by thecontrol data creating unit 221. The UL scheduling unit 219 performsscheduling for mapping user data to individual uplink channels, on thebasis of the uplink radio channel estimation result received from thereception processing units 205-1 to 205-5 and radio resource allocationrequests from the mobile station apparatuses 1, and supplies ascheduling result to the control unit 213. In a case where the ULscheduling unit 219 is notified from the preamble detecting units 211that a random access preamble has been detected, the UL scheduling unit219 allocates the physical uplink shared channel PUSCH, and notifies thecontrol data creating unit 221 of the allocated physical uplink sharedchannel PUSCH and a preamble number (sequence number).

The cell management unit 223 manages individual cells and systeminformation about the cells (for example, configuration informationabout physical channels, transmission power information about individualchannels, and random access information). Also, the cell management unit223 allocates cells to the mobile station apparatus 1, and determines acell for which random access is permitted among the allocated cells.Then, the cell management unit 223 supplies system information to thecontrol data creating unit 221 to notify the control data creating unit221 of the system information about the allocated cells. The systeminformation about the cell for which random access is permitted includesrandom access information (arrangement information about random accesschannels RACH, random access preamble generation information, andtransmission information about a random access preamble, such as themaximum number of transmissions of a random access preamble andtransmission power for the random access preamble). The systeminformation about the cell for which random access is not permitted doesnot include random access information. Also, in the case of allowing themobile station apparatus 1 to execute random access, the cell managementunit 223 selects a dedicated sequence (dedicated preamble) and theposition of a random access channel RACH, and supplies the selecteddedicated sequence number and random access channel number to thecontrol data creating unit 221.

The control data creating unit 221 creates control data to be set to thephysical downlink control channel PDCCH and control data to be set tothe physical downlink shared channel PDSCH. The control data creatingunit 221 creates control data, such as a control message includingscheduling information; ACK/NACK of uplink data; a system informationmessage including configuration information about physical channels,transmission power information about individual channels, and randomaccess information; an initial setting message including settinginformation about a cell to be used (including random accessinformation); a random access response message including a preamblenumber, transmission timing information, and scheduling information; acontention resolution message; and a message including a dedicatedsequence number, a random access channel number, and a random accessinstruction.

In a case where the preamble detecting units 211-1 to 211-5 detect arandom access preamble in a random access channel RACH, the preambledetecting units 211-1 to 211-5 calculate an amount of difference intransmission timing on the basis of the detected random access preamble,and notify the scheduling unit 215 of the cell in which the randomaccess preamble has been detected, a detected preamble number (sequencenumber), and the amount of difference in transmission timing.

Description of Operation

A radio communication system which uses the random access proceduresillustrated in FIGS. 7 and 8 is assumed. Also, a radio communicationsystem in which the base station apparatus 3 and the mobile stationapparatus 1 communicate with each other by using a plurality of cellsamong which the transmission timing in the mobile station apparatus 1varies, as illustrated in FIGS. 10, 11, and 12, is assumed.

In Advanced-EUTRA, the base station apparatus 3 allocates one or morecells of different frequencies suitable for the communication capacityand communication condition of the mobile station apparatus 1 among aplurality of cells for each frequency, and the mobile station apparatus1 transmits and receives data by using the allocated cell or cells. In acase where the mobile station apparatus 1 communicates with the basestation apparatus 3 by using a plurality of cells, the mobile stationapparatus 1 may connect to the base station apparatus 3 via a repeateror the like, as illustrated in FIG. 12. In such a case, the receptiontiming of a downlink component carrier in the mobile station apparatus 1may vary among individual cells. Furthermore, the transmission timingfor the base station apparatus 3 may vary among individual uplinkcomponent carriers of individual cells. If the transmission timing ofeach uplink component carrier for the base station apparatus 3 varies,it is necessary for the mobile station apparatus 1 to adjusttransmission timings in individual uplink component carriers ofindividual cells.

However, in a case where it is necessary to adjust the transmissiontiming in the mobile station apparatus 1 in individual cells, if uplinksynchronization is lost, for example, at the time of initial access orhandover, random access processing is required for each cell. In a casewhere each mobile station apparatus 1 is allocated with a plurality ofcells and where random access processing operations are simultaneouslyexecuted in the individual cells, the processing executed in the mobilestation apparatus 1 becomes complicated. In addition, since each mobilestation apparatus 1 executes a plurality of random access processingoperations, the probability of the occurrence of collision of randomaccess preambles among the mobile station apparatuses 1 increases, andthe occurrence of collision of random access preambles in the entirecells increases. Thus, the opportunities of transmitting an unnecessaryrandom access preamble are decreased by restricting execution of randomaccess by the mobile station apparatuses 1.

The base station apparatus 3 groups cells into groups in each of whichcells have an identical transmission timing in the mobile stationapparatus 1 (hereinafter referred to as transmission timing cellgroups). The base station apparatus 3 permits random access for one cellin each transmission timing cell group. The base station apparatus 3notifies the mobile station apparatus 1 of system information about onlythe cell for which random access is permitted, the system informationincluding random access information (arrangement information aboutrandom access channels RACH, random access preamble generationinformation, the maximum number of transmissions of a random accesspreamble, transmission power information about a random access preamble,and so forth). Accordingly, the mobile station apparatus 1 is incapableof executing random access using a cell whose random access informationis not available, and thus execution of random access can be restricted,and unnecessary random access can be prevented. Note that the systeminformation is information constituting a cell, such as configurationinformation about uplink/downlink physical channels and transmissioninformation about uplink/downlink physical channels. The random accessinformation is information that is necessary for executing a randomaccess procedure related to transmission of a random access preamble,such as arrangement information about random access channels RACH,information for generating a random access preamble, and informationabout the maximum number of transmissions of a random access preambleand transmission power.

Furthermore, the base station apparatus 3 permits both of contentionbased random access and non-contention based random access for one ofthe cells for which random access by the mobile station apparatus 1 ispermitted, and permits non-contention based random access for the othercells for which random access is permitted. Accordingly, the mobilestation apparatus 1 is incapable of executing random access using a cellfor which only non-contention based random access is permitted, as longas an instruction is not provided from the base station apparatus 3, andthus execution of random access can be restricted.

Alternatively, the random access to be permitted may be specified foreach transmission timing cell group. That is, the base station apparatus3 is capable of restricting execution of random access from the mobilestation apparatus 1 by permitting both of contention based random accessand non-contention based random access, or non-contention based randomaccess for each of the cells for which random access is permitted.Alternatively, the base station apparatus 3 may enable selection of onlycontention based random access.

The operations of the mobile station apparatus 1-1 and the base stationapparatus 3 will be described. The base station apparatus 3 isconstituted by, for example, cells #1 to #5, as illustrated in FIG. 3A.Cells #1 to #3 form a cell group of an identical transmission timing,and cells #4 and #5 form another cell group of an identical transmissiontiming.

The mobile station apparatus 1-1 executes cell search, and finds one ofthe cells of the base station apparatus 3. Here, it is assumed that themobile station apparatus 1-1 finds cell #1. The mobile station apparatus1-1 obtains system information about cell #1 (physical channelconfiguration of the cell, transmission power information, random accessinformation, etc.) from the physical broadcast channel PBCH of cell #1.Then, by using the random access information included in the systeminformation, the mobile station apparatus 1-1 transmits a random accesspreamble to the random access channel RACH of cell #1 for initialaccess. Then, the mobile station apparatus 1-1 obtains random accessresponse information including transmission timing information aboutcell #1 from the base station apparatus 3, sets a transmission timing ofan uplink component carrier for cell #1, and starts a transmissiontiming timer. The mobile station apparatus 1-1 transmits a message 3 tothe base station apparatus 3 via cell #1. The message 3 includes thecontent representing initial access. Upon receiving a contentionresolution from the base station apparatus 3, the mobile stationapparatus 1-1 ends the contention based random access procedure.

After the random access procedure has been completed, the base stationapparatus 3 allocates the cells to be used by the mobile stationapparatus 1-1, and notifies the mobile station apparatus 1-1 of thesystem information about the cells to be used by the mobile stationapparatus 1-1. Here, the base station apparatus 3 notifies the mobilestation apparatus 1-1 by including, in the system information, randomaccess information about only the cells for which random access ispermitted in individual transmission timing cell groups. The mobilestation apparatus 1-1 recognizes that random access is permitted for thecells whose random access information is included in the systeminformation among the allocated cells. Also, the base station apparatus3 notifies the mobile station apparatus 1-1 of information indicatingthat both of contention based random access and non-contention basedrandom access are permitted for the cells for which random access ispermitted, or information indicating that non-contention based randomaccess is permitted. Alternatively, the base station apparatus 3 maynotify the mobile station apparatus 1-1 of only information indicatingthat both of contention based random access and non-contention basedrandom access are permitted for one of the cells for which random accessis permitted, so that the mobile station apparatus 1-1 recognizes thatonly non-contention based random access is permitted for the other cellsfor which random access is permitted.

Here, as illustrated in FIG. 3B, the base station apparatus 3 allocatescells #1 to #5 to the mobile station apparatus 1-1, and permitscontention based random access and non-contention based random accessfor cell #1, and permits non-contention based random access for cell #5.The base station apparatus 3 notifies the mobile station apparatus 1-1of setting information, such as the system information about theallocated cells and group information about the transmission timing cellgroups. Here, the base station apparatus 3 notifies the mobile stationapparatus 1-1 without including random access information in the systeminformation about cells for which random access is not permitted. Here,the base station apparatus 3 does not notify the mobile stationapparatus 1-1 of random access information about cells #2, #3, and #4.The mobile station apparatus 1-1 recognizes that random access is notpermitted for the cells whose random access information is not includedin the system information among the allocated cells.

After obtaining the allocated system information and the groupinformation about the transmission timing cell groups, the mobilestation apparatus 1-1 sets the transmission timing of cell #1 as theuplink transmission timings of cells #2 and #3, which are in the sametransmission timing cell group as cell #1. After that, data istransmitted and received between the mobile station apparatus 1-1 andthe base station apparatus 3 via the downlink component carriers ofcells #1 to #5 and the uplink component carriers of cells #1 to #3.

In a case where the amount of data transmitted from the mobile stationapparatus 1-1 increases and where there is a cell which is not used bythe mobile station apparatus 1-1, the base station apparatus 3 notifies,by using the physical downlink control channel PDCCH, the mobile stationapparatus 1-1 of random access instruction information for providing aninstruction to execute non-contention based random access using the cellfor which random access is permitted. Here, the base station apparatus 3notifies the mobile station apparatus 1-1 of the random accessinstruction information about cell #5. The random access instructioninformation includes a preamble number and a random access channelnumber. The mobile station apparatus 1-1 determines the preamble number,and, if the preamble number indicates non-contention based randomaccess, the mobile station apparatus 1-1 transmits a random accesspreamble to the random access channel RACH of cell #5 by using thepreamble and random access channel specified by the base stationapparatus 3. The base station apparatus 3 notifies the mobile stationapparatus 1-1 of the random access instruction information by using thedownlink component carrier of the cell which is a target of randomaccess.

Upon detecting the random access preamble, the base station apparatus 3calculates a transmission timing on the basis of the random accesspreamble, and transmits a random access response including transmissiontiming information to the mobile station apparatus 1-1 via the downlinkcomponent carrier of cell #5. Upon receiving the random access response,the mobile station apparatus 1-1 sets the transmission timing includedin the random access response as the transmission timing of the uplinkof cell #5 and as the transmission timing of the uplink of cell #4 inthe same transmission timing cell group, and starts a transmissiontiming timer. Then, the mobile station apparatus 1-1 completes thenon-contention based random access procedure. After that, data istransmitted and received between the mobile station apparatus 1-1 andthe base station apparatus 3 also by using the uplink component carriersof cells #4 and #5.

The mobile station apparatus 1-1 has one transmission timing timer foreach transmission timing cell group, and starts or restarts thetransmission timing timer upon receiving transmission timinginformation. While the transmission timing timer is running, uplinksynchronization is achieved (transmission timing is valid), and uplinktransmission on the uplink component carriers of a target transmissiontiming cell group is possible. While the timer is stopped, uplinksynchronization is lost (transmission timing is invalid), and uplinkdata transmission on the uplink component carriers of a targettransmission timing cell group is impossible, except for transmission ofa random access preamble.

The mobile station apparatus 1-1 does not execute a random accessprocedure when receiving random access instruction information regardinga cell other than a cell for which random access is permitted. Also, themobile station apparatus 1-1 does not execute a random access procedurewhen receiving random access instruction information for providing aninstruction to execute contention based random access regarding a cellfor which only non-contention based random access is permitted.

In a case where uplink transmission data is newly generated in a statewhere there is no allocation of a physical uplink shared channel PUSCHfrom the base station apparatus 3 and where uplink synchronization isachieved (transmission timing is valid) or is not achieved (transmissiontiming is invalid), the mobile station apparatus 1-1 executes contentionbased random access as a scheduling request. At this time, the mobilestation apparatus 1-1 selects a cell for which contention based randomaccess is permitted for the uplink component carrier of the cell used inrandom access. Here, the mobile station apparatus 1-1 selects cell #1.Then, the mobile station apparatus 1-1 selects one random sequence byusing random access information about the cell for which contentionbased random access is permitted, generates a random access preamble,and transmits the random access preamble to the random access channelRACH of cell #1.

Upon receiving a random access response from the base station apparatus3 via the downlink component carrier of cell #1, the mobile stationapparatus 1-1 sets obtained transmission timing information as an uplinktransmission timing of cell #1 and as uplink transmission timings ofcells #2 and #3 in the same transmission timing group, and starts atransmission timing timer. Then, the mobile station apparatus 1-1includes transmission buffer status information about the mobile stationapparatus 1-1 in a message 3, and notifies the base station apparatus 3of the message 3. The mobile station apparatus 1-1 ends contention basedrandom access upon receiving a contention resolution from the basestation apparatus 3.

The base station apparatus 3 may change the cell for which random accessis permitted, in accordance with an access status of the random accesschannel RACH. In the case of changing the cell for which random accessis permitted, the base station apparatus 3 notifies the mobile stationapparatus 1-1 of random access information about the cell for whichrandom access is newly permitted. The mobile station apparatus 1-1 setsthe obtained random access information, and deletes old random accessinformation.

For example, in the case of changing cell #5 for which non-contentionbased random access is permitted to cell #4, the base station apparatus3 notifies the mobile station apparatus 1-1 of random access informationabout cell #4. Upon receiving the random access information about cell#4, the mobile station apparatus 1-1 sets the random access informationabout cell #4, and deletes the random access information about cell #5.At this time, the mobile station apparatus 1-1 recognizes that the cellfor which random access is permitted has changed within the sametransmission timing cell group, and performs setting under theassumption that the random access which is permitted for cell #4 isnon-contention based random access. The mobile station apparatus 1-1does not change the setting of a cell for which random access ispermitted in different transmission timing cell groups. Additionally, inthe case of changing a permitted random access procedure, informationindicating the permitted random access procedure is also notified.

In a case where the mobile station apparatus 1-1 receives, from the basestation apparatus 3, random access instruction information about a cellfor which non-contention based random access is permitted duringprocessing of a contention based random access procedure, the mobilestation apparatus 1-1 continues the contention based random accessprocessing which is being executed and ignores the ransom accessinstruction information from the base station apparatus 3, or stops thecontention based random access processing which is being executed andperforms random access using the cell specified in accordance with therandom access instruction information received from the base stationapparatus 3. In a case where the mobile station apparatus 1-1 receivesrandom access instruction information about a cell during random accessprocessing which is based on random access instruction information fromthe base station apparatus 3, the mobile station apparatus 1-1 placespriority on the first random access instruction and ignores thesubsequent random access instruction information. In this way, themobile station apparatus 1-1 does not simultaneously execute a pluralityof random access processing operations.

Also, regarding random access using a cell for which both of contentionbased random access and non-contention based random access arepermitted, if the number of transmissions of a random access preambleexceeds the maximum number of transmissions, the base station apparatus1-1 determines that random access has failed. However, regarding randomaccess using a cell for which non-contention based random access ispermitted, the mobile station apparatus 1-1 does not determine thatrandom access has failed even if the number of transmissions of a randomaccess preamble exceeds the maximum number of transmissions. With thisconfiguration, the occurrence of random access failure can besuppressed.

In the above-described embodiment, description has been given of amethod for restricting random accesses by permitting contention basedrandom access and non-contention based random access for one cell in onetransmission timing cell group and by permitting non-contention basedrandom access for one cell in each of the other transmission timing cellgroups. Alternatively, contention based random access may be randomaccess which is based on a scheduling request, and non-contention basedrandom access may be random access which is based on random accessinstruction information. That is, random accesses can be restricted bypermitting random access which is based on a scheduling request andrandom access which is based on random access instruction informationfor one cell in one transmission timing cell group and by permittingrandom access which is based on random access instruction informationfor one cell in each of the other transmission timing cell groups.

Accordingly, unnecessary random access does not occur. Also, the mobilestation apparatuses 1 do not need to simultaneously execute randomaccess processing, and thus random access processing in the mobilestation apparatuses 1 can be prevented from being complicated.

Second Embodiment Description of Configuration

The configuration of the mobile station apparatus 1 according to asecond embodiment of the present invention is the same as that inFIG. 1. The mobile station apparatus 1 includes the radio unit 101, thetransmission processing units 103-1 to 103-5, the reception processingunits 105-1 to 105-5, the transmission data control unit 107, thecontrol data extracting unit 109, the random access preamble generatingunit 111, the transmission timing adjusting units 113-1 to 113-5, thecontrol unit 115, and the scheduling unit 117. The scheduling unit 117includes the control data analyzing unit 119, the UL scheduling unit121, the control data creating unit 123, and the cell management unit125. In this embodiment, in order to describe an example in which themobile station apparatus 1 is capable of receiving signals using fivecells, five transmission processing units 103, five reception processingunits 105, and five transmission timing adjusting units 113 areprovided.

The operations of the radio unit 101, the transmission processing units103-1 to 103-5, the reception processing units 105-1 to 105-5, thetransmission data control unit 107, the control data extracting unit109, the random access preamble generating unit 111, the transmissiontiming adjusting units 113-1 to 113-5, and the control unit 115 are thesame as the operations described above with reference to FIG. 1, andthus the description thereof is omitted.

The scheduling unit 117 includes the control data analyzing unit 119,the UL scheduling unit 121, the control data creating unit 123, and thecell management unit 125. The control data creating unit 123 createscontrol data, and creates a response to downlink data received by thecontrol data extracting unit 109. The control data analyzing unit 119analyzes the control data received from the control data extracting unit109. The control data analyzing unit 119 supplies system informationabout the cells, allocation information about the cells, a random accessresponse message, and random access instruction information which arereceived from the base station apparatus 3 to the cell management unit125, and supplies random access information included in the systeminformation to the random access preamble generating unit 111.

The UL scheduling unit 121 controls the transmission data control unit107 on the basis of scheduling information about uplink data. Also, theUL scheduling unit 121 instructs the cell management unit 125 to executerandom access on the basis of control information received from an upperlayer.

The cell management unit 125 manages the cells which are set by the basestation apparatus 3, and manages system information notified from thebase station apparatus 3, such as the configuration of physical channelsof the individual cells, transmission power information, and randomaccess information. Also, the cell management unit 125 manages theoperations of the mobile station apparatus 1 for each of a first cell,second cell, and third cell. In a case where random access to the basestation apparatus 3 is executed, the cell management unit 125 determinesa cell with which a random access preamble is to be transmitted,randomly selects a sequence to be used on the basis of the downlinkradio channel characteristic information received from the receptionprocessing units 105-1 to 105-5 and the transmission data size of themessage 3 by using random access information about the cell to be usedfor random access, and notifies the random access preamble generatingunit 111 of information about the selected cell and a sequence number(preamble number). The details of random access will be described below.

Also, the cell management unit 125 determines the content of the randomaccess response received from the control data analyzing unit 119. Whenthe cell management unit 125 detects the preamble number of thetransmitted random access preamble, the cell management unit 125supplies transmission timing information to any of the transmissiontiming adjusting units 113-1 to 113-5 related to the cell used forrandom access, and supplies allocated radio resource information to theUL scheduling unit 121. After determining a contention resolutionmessage, the cell management unit 125 ends the random access procedure.Also, the cell management unit 125 extracts a sequence number (preamblenumber) and a random access channel number from the random accessinstruction information received from the control data analyzing unit119, and supplies the cell information, the sequence number (preamblenumber), and the random access channel number to the random accesspreamble generating unit 111.

The sequence selected by the mobile station apparatus 1 is referred toas a random sequence (random preamble), and the sequence specified bythe base station apparatus 3 is referred to as a dedicated sequence(dedicated preamble). In a case where a cell to be used is not specifiedby the base station apparatus 3, the mobile station apparatus 1 executesrandom access by using the uplink component carrier of the cell withwhich the random access instruction information has been received. Also,in a case where a sequence to be used is not specified, the mobilestation apparatus 1 selects a sequence from among random sequences.

The configuration of the base station apparatus 3 according to thesecond embodiment of the present invention is the same as thatillustrated in FIG. 2. The base station apparatus 3 includes the radiounit 201, the transmission processing units 203-1 to 203-5, thereception processing units 205-1 to 205-5, the transmission data controlunit 207, the control data extracting unit 209, the preamble detectingunits 211-1 to 211-5, the control unit 213, and the scheduling unit 215(base-station-side scheduling unit). The scheduling unit 215 includesthe DL scheduling unit 217, the UL scheduling unit 219, the control datacreating unit 221, and the cell management unit 223. In this embodiment,an example of a case where the base station apparatus 3 has five cellsis described, and thus five transmission processing units 203, fivereception processing units 205, and five preamble detecting units 211are provided.

The operations of the radio unit 201, the transmission processing units203-1 to 203-5, the reception processing units 205-1 to 205-5, thetransmission data control unit 207, the control data extracting unit209, the preamble detecting units 211-1 to 211-5, and the control unit213 are the same as those described above with reference to FIG. 2, andthus the description of the operations is omitted.

The scheduling unit 215 includes the DL scheduling unit 217 whichperforms downlink scheduling, the UL scheduling unit 219 which performsuplink scheduling, the control data creating unit 221, and the cellmanagement unit 223. The DL scheduling unit 217 performs scheduling formapping user data and control data to individual downlink channels, onthe basis of the downlink radio channel information notified from themobile station apparatuses 1, data information about individual usersnotified from an upper layer, and the control data created by thecontrol data creating unit 221. The UL scheduling unit 219 performsscheduling for mapping user data to individual uplink channels, on thebasis of the uplink radio channel estimation result received from thereception processing units 205-1 to 205-5 and radio resource allocationrequests from the mobile station apparatuses 1, and supplies ascheduling result to the control unit 213. In a case where the ULscheduling unit 219 is notified from the preamble detecting units 211that a random access preamble has been detected, the UL scheduling unit219 allocates the physical uplink shared channel PUSCH, and notifies thecontrol data creating unit 221 of the allocated physical uplink sharedchannel PUSCH and a preamble number (sequence number).

The cell management unit 223 manages individual cells and systeminformation about the cells (for example, configuration informationabout physical channels, transmission power information about individualchannels, and random access information). Also, the cell management unit223 allocates cells to the mobile station apparatus 1, and determines afirst cell, second cell, and third cell among the allocated cells. Then,the cell management unit 223 supplies system information to the controldata creating unit 221 to notify the control data creating unit 221 ofthe system information about the allocated cells. The system informationabout the first cell and the second cell includes random accessinformation (arrangement information about random access channels RACH,random access preamble generation information, and random accesspreamble transmission information, such as the maximum number oftransmissions of a random access preamble and transmission power for therandom access preamble). The system information about the third celldoes not include random access information. Also, in the case ofallowing the mobile station apparatus 1 to execute random access, thecell management unit 223 selects a dedicated sequence (dedicatedpreamble) and the position of a random access channel RACH, and suppliesthe selected dedicated sequence number and random access channel numberto the control data creating unit 221.

The control data creating unit 221 creates control data to be set to thephysical downlink control channel PDCCH and control data to be set tothe physical downlink shared channel PDSCH. The control data creatingunit 221 creates control data, such as a control message includingscheduling information; ACK/NACK of uplink data; a system informationmessage including configuration information about physical channels,transmission power information about individual channels, and randomaccess information; an initial setting message including settinginformation about a cell to be used (including random accessinformation); a random access response message including a preamblenumber, transmission timing information, and scheduling information; acontention resolution message; and a message including a dedicatedsequence number, a random access channel number, and a random accessinstruction.

Description of Operation

In this embodiment, description will be given of a cell managementmethod including a random access restriction method. The base stationapparatus 3 groups a plurality of cells into a plurality of transmissiontiming cell groups in each of which cells have an identical transmissiontiming. In the case of allocating a plurality of cells to the mobilestation apparatus 1, the base station apparatus 3 sets one of the cellsin one of the plurality of transmission timing cell groups as a firstcell. Also, the base station apparatus 3 sets one of the cells in eachof the other transmission timing cell groups as second cells, and setsthe cells other than the first and second cells as third cells.

The base station apparatus 3 is configured to permit contention basedrandom access and non-contention based random access for the first cell.Also, the base station apparatus 3 notifies the base station apparatus 1of update information of system information about the individual cellsvia the first cell, and arranges the physical uplink control channelPUCCH to be used by the mobile station apparatus 1 on the physicaluplink control channel PUCCH of the first cell. The base stationapparatus 3 is configured to permit non-contention based random accessfor the second cells. Also, the base station apparatus 3 notifies themobile station apparatus 1 of transmission timing information via thefirst and second cells. The base station apparatus 3 is configured notto permit random access for the third cells. The mobile stationapparatus 1 determines whether of not random access has failed in thefirst cell, and does not determine whether or not random access hasfailed in the second cells. Also, the mobile station apparatus 1determines a radio quality error of downlink in the first cell, and doesnot determine a radio quality error of downlink in the second and thirdcells.

In this way, necessary functions are set in the order of the first cell,second cells, and third cells, and an important function is set to thefirst cell, so that the cells can be easily managed. Also, with thismethod, the restriction of random access and the management of randomaccess failure described in the first embodiment can be performed.

The operations of the mobile station apparatus 1-1 and the base stationapparatus 3 will be described. For example, it is assumed that the basestation apparatus 3 is constituted by cells #1 to #5, as illustrated inFIG. 4A, and that cells #1 and #2 are in the cell group of an identicaltransmission timing (first transmission timing cell group), cells #3 and#4 are in the cell group of an identical transmission timing (secondtransmission timing cell group), and cell #5 is in the cell group of anidentical transmission timing (third transmission timing cell group).

The mobile station apparatus 1-1 executes cell search, and finds one ofthe cells of the base station apparatus 3. Here, it is assumed that themobile station apparatus 1-1 finds cell #2. The mobile station apparatus1-1 obtains system information about cell #2 (physical channelconfiguration of the cell, transmission power information, random accessinformation, etc.) from the physical broadcast channel PBCH of cell #2.Then, by using the random access information included in the systeminformation, the mobile station apparatus 1-1 transmits a random accesspreamble to the random access channel RACH of cell #2 for initialaccess. Then, the mobile station apparatus 1-1 obtains random accessresponse information including transmission timing information aboutcell #2 from the base station apparatus 3, sets a transmission timing ofan uplink component carrier for cell #2, and starts a transmissiontiming timer. The mobile station apparatus 1-1 transmits a message 3 tothe base station apparatus 3 via cell #2. The message 3 includes thecontent representing initial access. Upon receiving a contentionresolution from the base station apparatus 3, the mobile stationapparatus 1-1 ends the contention based random access procedure.

After the random access procedure has been completed, the base stationapparatus 3 allocates the cells to be used by the mobile stationapparatus 1-1, and also sets first, second, and third cells. Here, asillustrated in FIG. 4B, the base station apparatus 3 allocates cells #1to #5 to the mobile station apparatus 1-1, and sets cell #2 as a firstcell, cells #4 and #5 as second cells, and cells #1 and #3 as thirdcells. Then, the base station apparatus 3 notifies the mobile stationapparatus 1-1 of setting information, such as system information aboutthe allocated cells and group information about the transmission timingcell groups. The base station apparatus 3 notifies the mobile stationapparatus 1-1 by including random access information in the systeminformation about the first and second cells, and by not includingrandom access information in the system information about the thirdcell. That is, the base station apparatus 3 does not notify the mobilestation apparatus 1-1 of random access information about cells #1 and#3. The setting information about the first cell includes allocationinformation about the physical uplink control channel PUCCH.

After obtaining the system information about the individual cells andthe group information about the transmission timing cell groups, themobile station apparatus 1-1 sets the transmission timing of the cellsin the same transmission timing cell group. Here, the mobile stationapparatus 1-1 sets the transmission timing of cell #2 as the uplinktransmission timing of cell #1. After that, user data is transmitted andreceived between the mobile station apparatus 1-1 and the base stationapparatus 3 via the downlink component carriers of cells #1 to #5 andthe uplink component carriers of cells #1 and #2.

In a case where the amount data transmitted from the mobile stationapparatus 1-1 increases, the base station apparatus 3 notifies themobile station apparatus 1-1 of random access instruction informationfor providing an instruction to execute non-contention based randomaccess using the second cell, via the physical downlink control channelPDCCH. Here, the base station apparatus 3 notifies the mobile stationapparatus 1-1 of the random access instruction information about cell#4. The random access instruction information includes a preamble numberand a random access channel number. The mobile station apparatus 1-1determines the preamble number. If the preamble number indicatesnon-contention based random access, the mobile station apparatus 1-1transmits a random access preamble to the random access channel RACH ofcell #4 by using the preamble and random access channel specified by thebase station apparatus 3.

Upon detecting the random access preamble, the base station apparatus 3calculates a transmission timing on the basis of the random accesspreamble, and transmits a random access response including transmissiontiming information to the mobile station apparatus 1-1 via the downlinkcomponent carrier of cell #4. Upon receiving the random access response,the mobile station apparatus 1-1 sets the transmission timing includedin the random access response as the transmission timing of the uplinkof cell #4 and as the transmission timing of the uplink of cell #3 inthe same transmission timing cell group, and starts a transmissiontiming timer. Then, the mobile station apparatus 1-1 ends the non-contention based random access procedure. After that, data istransmitted and received between the mobile station apparatus 1-1 andthe base station apparatus 3 also by using the uplink component carriersof cells #3 and #4. In a case where a cell to be used for uplinktransmission is further required, the base station apparatus 3 notifiesthe mobile station apparatus 1-1 of random access instructioninformation for providing an instruction to execute non-contention basedrandom access using cell #5 as the second cell, by using the physicaldownlink control channel PDCCH of cell #5.

The mobile station apparatus 1-1 has one transmission timing timer foreach transmission timing cell group, and starts or restarts thetransmission timing timer upon receiving transmission timinginformation. While the transmission timing timer is running, uplinksynchronization is achieved (transmission timing is valid), and uplinktransmission on the uplink component carriers of a target transmissiontiming cell group is possible. While the timer is stopped, uplinksynchronization is lost (transmission timing is invalid), and uplinkdata transmission on the uplink component carriers of a targettransmission timing cell group is impossible.

The mobile station apparatus 1-1 does not execute a random accessprocedure when receiving random access instruction information regardinga third cell. Also, the mobile station apparatus 1-1 does not execute arandom access procedure when receiving random access instructioninformation for providing an instruction to execute contention basedrandom access regarding a second cell.

In a case where uplink transmission data is newly generated in a statewhere there is no allocation of a physical uplink shared channel PUSCHfrom the base station apparatus 3 and where uplink synchronization isachieved (transmission timing is valid) or is not achieved (transmissiontiming is invalid), the mobile station apparatus 1-1 executes contentionbased random access as a scheduling request. At this time, the mobilestation apparatus 1-1 selects the first cell. Here, the mobile stationapparatus 1-1 selects cell #2. Then, the mobile station apparatus 1-1selects one random sequence by using random access information about thefirst cell, generates a random access preamble, and transmits the randomaccess preamble to the random access channel RACH of the first cell.Then, upon receiving a random access response from the base stationapparatus 3 via the downlink component carrier of the first cell, themobile station apparatus 1-1 sets transmission timing informationincluded in the random access response as an uplink transmission timingof the first cell and as an uplink transmission timing of the cell inthe same transmission timing group, and starts a transmission timingtimer. Then, the mobile station apparatus 1-1 includes transmissionbuffer status information about the mobile station apparatus 1-1 in amessage 3, and notifies the base station apparatus 3 of the message 3.The mobile station apparatus 1-1 ends contention based random accessupon receiving a contention resolution from the base station apparatus3.

The base station apparatus 3 may change the first cell or second cell,in accordance with a radio channel condition or a communication status.In the case of changing the first cell, the base station apparatus 3notifies the mobile station apparatus 1-1 of allocation informationabout the physical uplink control channel PUCCH for a new first cell andrandom access information about the new first cell. The mobile stationapparatus 1-1 sets the obtained allocation information about thephysical uplink control channel PUCCH and random access information,releases the radio resource of the uplink PUCCH allocated to the oldfirst cell, and deletes random access information about the old firstcell. Also, the mobile station apparatus 1-1 recognizes the change ofthe first cell by being allocated with the physical uplink controlchannel PUCCH.

In the case of changing the second cell, the base station apparatus 3notifies the mobile station apparatus 1-1 of random access informationabout a new second cell. The mobile station apparatus 1-1 sets theobtained random access information, and deletes random accessinformation about the old second cell. Also, the mobile stationapparatus 1-1 recognizes the change of the second cell by not beingallocated with the physical uplink control channel PUCCH.

For example, in the case of changing cell #2 as the first cell to cell#1, the base station apparatus 3 notifies the mobile station apparatus1-1 of the allocation information about the physical uplink controlchannel PUCCH of cell #1 and the random access information about cell#1. Upon receiving the allocation information about the physical uplinkcontrol channel and the random access information about cell #1, themobile station apparatus 1-1 sets the random access information aboutcell #1, releases the radio resource of the physical uplink controlchannel PUCCH which has been allocated to cell #2, and deletes therandom access information about cell #2.

In a case where the mobile station apparatus 1-1 receives random accessinstruction information about the first cell or second cell from thebase station apparatus 3 during processing of a random access procedure,the mobile station apparatus 1-1 continues the random access processingwhich is being executed and ignores the random access instructioninformation received from the base station apparatus 3, or stops therandom access processing which is being executed and executes randomaccess by using the cell specified in accordance with the random accessinstruction information received from the base station apparatus 3. Inthis way, the mobile station apparatus 1-1 does not simultaneouslyexecute a plurality of random access processing operations.

Also, regarding random access using the first cell, if the number oftransmissions of a random access preamble exceeds the maximum number oftransmissions, the base station apparatus 1-1 determines that randomaccess has failed. However, regarding random access using the secondcell, the mobile station apparatus 1-1 does not determine that randomaccess has failed even if the number of transmissions of a random accesspreamble exceeds the maximum number of transmissions. With thisconfiguration, the occurrence of random access failure can besuppressed.

In the above-described embodiment, description has been given of amethod for restricting random accesses by permitting contention basedrandom access and non-contention based random access for the first celland by permitting non-contention based random access for the secondcell. Alternatively, contention based random access may be random accesswhich is based on a scheduling request, and non-contention based randomaccess may be random access which is based on random access instructioninformation. That is, random accesses can be restricted by permittingrandom access which is based on a scheduling request and random accesswhich is based on random access instruction information for the firstcell and by permitting random access which is based on random accessinstruction information for the second cell.

In this way, necessary functions are set in the order of the first cell,second cells, and third cells, and an important function is set to thefirst cell, so that the cells can be easily managed. Also, with thismethod, the restriction of random access and the management of randomaccess failure can be performed.

An embodiment of the present invention has been described in detail withreference to the drawings. The specific configuration is not limited tothat described above, and various changes in design can be made withoutdeviating from the gist of the present invention.

For the convenience of description, the mobile station apparatus 1-1 andthe base station apparatus 3 according to the embodiment have beendescribed by using functional block diagrams. A program for realizingthe functions of the individual units of the mobile station apparatus1-1 and the base station apparatus 3 or part of these functions may berecorded on a computer-readable recording medium, the program recordedon the recording medium may be caused to be read into a computer systemso as to be executed, and thereby the mobile station apparatus 1 and thebase station apparatus 3 may be controlled. Here, the “computer system”includes hardware, such as an OS and peripheral devices.

The “computer-readable recording medium” is a portable medium, such as aflexible disk, a magneto-optical disk, a ROM, or a CD-ROM, or a storagedevice such as a hard disk built in the computer system. Furthermore,the “computer-readable recording medium” includes a medium whichdynamically holds a program for a short time, such as a communicationline used for transmitting a program via a network such as the Internetor a communication line such as a telephone line, and a medium whichholds a program for a certain period, such as a volatile memory in thecomputer system serving as a server or a client in that case. Theabove-described program may be used for realizing part of theabove-described function, and may be a program with which theabove-described functions can be realized in combination with a programwhich has already been recorded in the computer system.

The individual functional blocks used in the above-described embodimentsmay be realized by an LSI, which is typically an integrated circuit. Theindividual functional blocks may be individually mounted on chips, orsome or all of them may be integrated to be mounted on a chip. A methodfor integration may be realized by a dedicated circuit or ageneral-purpose processor, as well as an LSI. In a case where theprogress of semiconductor technologies produces an integrationtechnology which replaces an LSI, an integrated circuit according to thetechnology can be used.

The embodiments of the present invention have been described in detailwith reference to the drawings. Specific configurations are not limitedto these embodiments, and design within a scope of the gist of thepresent invention is included in the claims.

REFERENCE SIGNS LIST

-   1, 1-1 to 1-3 mobile station apparatus-   3 base station apparatus-   5-1, 5-2 repeater-   101, 201 radio unit-   103-1 to 103-5, 203-1 to 203-5 transmission processing unit-   105-1 to 105-5, 205-1 to 205-5 reception processing unit-   117, 215 scheduling unit

What is claimed is:
 1. A mobile station apparatus applied to a mobilecommunication system in which a plurality of cells are allocated to themobile station apparatus, the plurality of cells grouped into aplurality of cell groups, the mobile station apparatus comprising:control circuitry configured to and/or programmed to perform both of acontention based random access procedure to a base station apparatus anda non-contention based random access procedure to the base stationapparatus, wherein both of the contention based random access procedureand the non-contention based random access procedure corresponds to atleast one of the cells which belongs to a first cell group of theplurality of the cell groups, and the control circuitry furtherconfigured to and/or programmed to perform a non-contention based randomaccess procedure to the base station apparatus, wherein thenon-contention based random access procedure corresponds to at least oneof the cells belonging to a second cell group other than the first cellgroup, the control circuitry further configured to and/or programmed to:in a case where the mobile station apparatus receives random accessinstruction information about one of at least one of the cells belongingto the second cell group during processing of the contention basedrandom access procedure, continue the contention based random accessprocedure which is being executed and ignore the random accessinstruction information, or stop the contention based random accessprocedure which is being executed and perform the non-contention basedrandom access procedure using the one of at least one of the cells.